Certain conveyors carrying articles being worked on are preferably stopped at regular intervals to facilitate the performance of work at a particular work station. For example, in certain container filling machines wherein an open container is delivered by conveyor to a a load location and is to be filled with a specific amount of the product to be packaged, the covneyor is preferably stopped so that the cotainer can be filled without spillage or loss. Conventional stop and go conveyors generally include complex and expensive brakes, clutches, limit switches and the like, which increase the cost of manufacture, as well as the problems of maintenance.